In a negative-pressure-type booster device, a check valve (valve mechanism) is installed between a negative pressure chamber in a housing and a negative pressure source outside the housing. For example, Japanese Utility Model Publication No. 60-24672 discloses a negative-pressure-type booster device in which a check valve is disposed in a hose. Meanwhile, in recent years, a mode in which a check valve is directly attached to a housing has also been developed. The check valve is formed separately from the hose and the housing, and is assembled and fixed to the hose or the housing. The check valve is configured to allow air to circulate from a negative pressure chamber to a negative pressure source and to prohibit air from circulating from the negative pressure source to the negative pressure chamber. As a result, the negative pressure chamber is maintained at an appropriate pressure (negative pressure).